1. Field of the Invention
This invention relates generally to a brake control device for vehicles and more particularly to a brake control device provided with a brake booster having an anti-skid actuating function.
2. Description of the Prior Art
In a conventional anti-skid control device, a master cylinder and a power piston of a brake booster fluidically separated therefrom are operatively connected to each other to thereby permit the master cylinder to be fluidly and operatively connected with wheel brakes. In the anti-skid actuation, a control valve of the brake booster and an actuating chamber for providing a high pressure to the power piston are separated by an anti-skid valve from each other, and this high pressure within the actuating chamber is decreased and again increased and the brake controlling is attained.
However, in this conventional anti-skid control device, the anti-skid valve is required to interpose between the actuating chamber and the control valve in addition to the control valve of the brake booster, and further a changeover valve according to the changing speed of the pressure is also required for changing the changing speed of the pressure according to the lock state of vehicle wheels. Accordingly, the structure is very complicated and is disadvantageous in space.
In this invention, the control valve and the anti-skid valve of the brake booster are formed integrally with each other, and this integrally formed pressure control valve is opened by a little force in proportion to the operating force of the brake booster and receives an electric signal of a controlling logic circuit communicated with a wheel sensor in the anti-skid actuation and is then retracted by a solenoid coil in accordance with the lock state of the vehicle wheel, whereby pump pressure proportionately generated by the operating force of the brake booster and acted on the power piston is capable of controlling in proportion to the signal of the controlling logic circuit so that a simplified structure which is low in cost may be provided.